Containers adapted to be opened without the use of auxiliary openers have found widespread acceptance and extensive use in the food packaging industry. Such containers are typically known as easy-open containers with perhaps the best example being the familiar pop-top beverage can often used to contain soft drinks and beer. In more recent years, ecological concerns over detachable pop-tops have given rise to development of easy-open containers having nondetachable opening tabs which remain with the container after it is opened such that the spent container and tab can be discarded as a unit after use.
Various easy-open container designs have become known in the industry. Most of these designs include a container end wall which has a selectively separable panel defined in the wall by a score line. Upon manipulation of an adjacent opening tab, the panel is at least partially separated from the end wall along the score line and can be torn away or pivoted into the container to provide an opening through which the container contents can be consumed or dispensed. Once opened, however, such containers are not easily resealed against spoilage, contamination and decarbonation such that their contents must either be completely consumed or discarded upon opening the container.
While consuming the entire contents of a newly opened container is no problem for some people, others find their appetites satisfied after consuming only part of the contents or for other reasons desire to set aside the container for later consumption. Under these conditions, it is desirable that the container be resealable after opening to maintain the freshness of its contents. Further, resealing a partially emptied container helps prevent spoilage, contamination, decomposition or decarbonation of the contents and resealing refrigerated containers helps prevent the taste of the contents from becoming stale due to commingling with odors of other foods in the refrigerator.
While resealing a glass or plastic bottle with a screw cap is a relatively simple matter, providing an easy-open beverage can which is also resealable has proved a mammoth problem in the beverage can industry. The separable panel of a typical easy-open can is usually deformed or positioned within the can upon opening and is thus unsuitable or unavailable to reseal the opened can. Prior attempts to provide means for resealing an opened can have generally included separate stoppers, purchased as accessories, which snap into the can opening in an attempt to seal the can. These stoppers have generally been inconvenient and ineffective since they are easily lost and often do not conform well with the shape of the can opening.
Attempts to provide an can opening assembly which also serves to selectively reseal the opened can have generally not met with acceptance. Examples of such attempts are illustrated in U.S. Pat. Nos. 3,880,319, 3,807,597, 4,232,797, 4,391,385, 3,281,024, 2,294,102, 3,804,278 and 4,673,099.